Leaning has been with Yorkshire since 2008, starting at under 15 level. He went on to play for the Yorkshire Academy in the Yorkshire ECB County Premier League, and the Yorkshire Second XI in the Second XI Championship, before making his List A debut against Warwickshire in August 2012 and his first-class debut against Surrey in June 2013. He became an established member of the Yorkshire side during the 2014 season.
In 2014, several York City F.C. fans sponsored Leaning in his first season as a full professional cricketer. His father Andy is a former player and goalkeeping coach of York.